Hydraulic eductor valve



Jan. 20, 1953 H.H. POORT ET AL 2,625,797

HYDRAULIC EDUCTOR VALVE Filed March 15, 1952 Henna HaromPooN" James H.Shuuex :5 16 M dz (\Wornag;

Patented Jan. 20, 1953 HYDRAULIC EDUCTOR VALVE Henry Harold Poort andJames H.

Shaver, Grand Haven, Mich., assignors to Dake Engine Company, acorporation of Michigan Application March 15, 1952, Serial No. 276,762

Claims.

This invention relates to a hydraulic eductor valve especially adaptedto be used with a hydraulic press to increase the speed of movement ofthe ram of the press as it approaches the work on the bed. In the use ofa hydraulic press it is customary to raise the ram a. considerabledistance above the work on the bed so that there is sufficient clearanceto remove and replace and adjust the work for a subsequent operation.For the working stroke of the ram it must move down to the work and thenconsiderable pressure is applied to accomplish the pressing operation.

It is desirable that movement of the ram from its raised position abovethe work downward into engagement therewith shall be as rapid aspossible to speed the operation and this movement of the ram prior toengagement with the work requires relatively little power.

The hydraulic pressure to move the ram of the press is produced by apump which has great pressure capacity but relatively small volume offlow resulting in a very slow movement of the ram from its raisedposition to the work causing considerable lost time in the pressingoperation.

With the use of the eductor valve of this invention the same highpressure, low volume pump is caused to flow a greatly increased volumeof liquid at relatively low pressure but sufficient to move the ram atgreatly increased speed until it reaches the work whereupon the eductionautomatically ceases and high pressure created by the pump is exerted toperform the pressing operation. It has been found that educed flow ofliq: uid in the pipe leading to the press will be at least five times asgreat as the normal delivery of the pump.

The invention is hereafter more fully described and particularly pointedout in the claims, reference being had to the accompanying drawing inwhich:

Fig. 1 is a longitudinal section of the eductor valve embodying thisinvention and,

Fig. 2 is a diagrammatic illustration of the valve with the environingmechanisms.

Like numbers refer to like parts in all of the figures.

The hydraulic press, which is of conventional structure. has a base I onwhich the work 2 is located, upright posts 3, and a head 4. The ram 5 isslidably mounted on the posts 3 and normally lifted by springs 8. Ahydraulic cylinder 1 is mounted on the head 4, within which is aconventional piston having a piston rod 8 connected to the ram 5.

The liquid used in the hydraulic operation may be of suitable nature,usually oil, has a supply reservoir or tank 10. A supply pipe ll extendsfrom the tank to the pump l2 and thence to the eductor valve 13 with amanual control valve [4 interposed by means of which operation of thepress may be controlled. The pipe 15 leads from the valve l3 to thecylinder I above the piston therein.

The eductor valve 13 has various passages, valves, inlets, outlets and anozzle hereafter described. The supply pipe ll communicates with apassage l6 leading to a passage I! in which is located a check valve 18.The passage [1 branches into the passage l9 which leads to the nozzle 20and the nozzle has its outlet in an induction chamber 2!. From thechamber 2| a reduced passage 22 in the form of a venturi leads to thechamber 23 which communicates with the pipe l5 leading to the hydrauliccylinder 1.

A branch passage 25 emerges laterally from the passage 16 and aconventional spring loaded safety valve 26 is located in and normallycloses the passage 25. The safety valve 26 has an outlet through thepassage 21 which communicates with the return pipe 28 leading to thetank l0. An eductor pipe 30 leads from the tank [0 and communicates withthe passage 3| in which is a check valve 32 and the passage 3| opensinto the chamber 2|. A passage 33 leads from the chamber 23 to ashut-off valve 34 which communicates with a return pipe 35 leading tothe tank 10. A hand operated screw 36 having a lever 31 has a tipped endwhich engages the shut-off valve 34 and holds it closed or may be turnedto release the valve.

Operation The shut-off valve 34 is closed by turning the screw 36 andassuming that the pump I2 is operating, the valve 14 is opened admittingoil into the passage 16. The oil is under sufficient pressure to openand pass by the check valve l8, flowing through the passages l1 and [9into the nozzle 20. The pump I2 is capable of creating high oil pressurewhich may be assumed to be 5,000 lb. per sq. in. and this may beconsidered as the working pressure of the hydraulic press. Therefore thespring tension of the safety valve 26 is set to hold that valve closedat pressure less than 5,000 lbs.

The volume capacity of the pump I2 is relatively small and the outletorifice of the nozzle 20 is small enough to retard the flow of oiltherethrough and to create a back pressure of about half the capacity ofthe pump or approximately 2,500 lbs. With this amount of pressure in theline the safety valve 26 will remain closed.

The oil under 2,500 lbs. pressure escapes through the nozzle 20 in asmall jet at high speed and in passing through the Venturi passage 20 itcreates a semivacuum in the induction chamber 2| which sucks or siphonoil from the tank I through the pipe 30, past the check valve 32, whichis freely movable, through the chamber 2| and out through the passage 22with the oil emerging from the nozzle 20 and the combined volumes of oilpass on through the chamber 23 and the pipe l5 into the upper end of thehydraulic cylinder 1.

The volume of oil educed by suction from the tank l0 by virtue of thehigh speed jet passing" through the venturi 22 is relatively great,being at least five times that of the jet from the nozzle and the forceof the jet is sufficient to carry the combined volume through the pipeI5 and into the cylinder 1 with enough pressure to lower the ram 5against the relatively small resistance I of the springs 5 and to movethe ram downward until it engages the work 2 andthis' preliminarymovement'ofthe ram is about six times as fast as it would move if onlythe volume of the pump i 2 were utilized for that-purpose.

For example, if the low volume pump could, a

with its own capacity, lower the ram six inches per minute the same pumpwith this eductor valve would lower the ram thirty-six inches perminute; If the ram were elevated eighteen inches above the work it wouldtake three minutes for the pump to lower the ram in its preliminarymovement. while with the eduction valve this movement is accomplished inthirty 'seconds.

When the ram 5 engages the \VOlk'Z resistance to its movementimmediately builds up pressure in the whole system, whereupon the siphoneduction of oil through'the pipe ceases and the checkvalve 32 is closedby such back pressure. After the check valve32 closes theoil flow in thewhole system isin accordance with the volume and pressure capacity ofthe pump l2 "which continues to force oil through the nozzle 20 untilthe compressing. operation of the press'is completed andpram 5 can moveno further. Then when the oil attains its-maximum pressure it will openthe safety valve 26 and'the continued now from the pump will" escapetherethrough and return to the tank lll through the pipe 28. Whenmovement of the ram ceases and the pressing operation is completed thevalve I4 may be closed and/or the operation of the pump stopped and thenthe oil in the cylinder 1- and pipe I5 is held under pressure by thecheck valves I8 and 32 which close and prevent escape of oil. When it isdesired to release theram and permit it to rise by action of thespringst, the screw is turned to release the shut-off valve 34 whichopens andpermits oil to flow from the cylinder fl through the pipelfiythe chamber 23, the passage 33 and out through the pipe 35 tobereturned'to" the-tank I 0.

ventionally used with a hydraulic press is automatically temporarilyconverted into a high volume low pressure pump for the purpose of fastmovement of the press ram in its preliminary movement to the work andthereafter the pump automatically resumes its high pressure low volumecharacter for exerting the necessary high pressure for the actualpressing operation. This is accomplished without" any alterationwhatever of the pump itself. The eductor valve is entirely automatic inits operation and is relatively simpler in construction and having nomoving parts excepting the check valves it is durable and long-lasting,and furthermore it is very simply installed in the hydraulic system ofthe hydraulic press.-

The invention is specifically defined in the appended claims and is tobe considered comprehensive of all forms coming within their scope.

We claim:

1. The combination with a hydraulic pump having a fluid reservoir and ahydraulic ram having" a cylinder and piston therein of an eduction valvecomprising, a body having an inlet passage iii-communicationwith saidpump and an outlet passage in communication'with said cylinder, aninduction chamber'interposed between said inlet and outlet passages, an'eduction conduit communicating between said reservoir and saidinduction chamber, a check valve in said eduction conduit opening in thedirection of flow toward said induction chamber, a Venturi passagecommunicating between said induction chamber and said outlet passage,and a nozzle in communication with said inlet passage and having itsoutlet in said induction chamber directed toward said Venturi passage.

2. The elements of claim 1 in which the outlet of said nozzle has a fiowcapacity considerably less than that of said pump.

3. The elements of claim 1 combined with a return conduit communicatingbetween said outlet passage and said'reservoir, and a manual shut-offvalve in said return conduit.

4. The elements of claim 1 combined with a check valve in the passagebetween said inlet and said nozzle opening in the direction of flowtoward said nozzle.

5. The elements of claim '1 combined with a spring pressed safety reliefvalve opening from the passage betweensaid inlet and said outlet andareturn'conduit leading from the outlet of said safety relief valve tosaid reservoir.

HENRYHAROLD POORT. JAMES H. SHAVER.

REFERENCES CITED The following references are of record'in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,982,711 7 Viclger Dec. 4, 19342,093,408 Batterson t Sept. 21, 1937 2,533,028 McConaghy Dec. 5, 1950

